Poster of the Nicaragua Earthquake of 9 October 2004 - Magnitude 6.9

Tectonic Summary

This thrust-fault earthquake occurred just east of the Middle America
Trench at the interface between the Cocos and the Caribbean plates.
The northwest-southeast trending trench marks the boundary where
the Cocos plate begins subducting beneath the overriding Caribbean
plate at a rate of about 80 millimeters per year. In addition to interface
thrust-fault earthquakes, shallow strike-slipearthquakes occur within
the deforming crust of the overriding Caribbean plate, and earthquakes
occur within the subducting Cocos plate from shallow depths to depths
of over 200 km. The world's largest earthquakes have been interface
thrust-fault earthquakes, including the 1960 magnitude 9.5 Chilean
earthquake and the 1964 magnitude 9.2 Alaskan earthquake. Historically,
however, the most damaging Nicaraguan earthquakes have been earthquakes
occurring beneath population centers at shallow depth in the Caribbean
plate. The 1972 magnitude 6.2 Managua earthquake, for example,
destroyed the center of the city and killed an estimated 6000 people.

Downloads

Settings

The posters may be downloaded for viewing or for printing on a color
plotter. Adobe PDF (.pdf) format files are provided. Adobe Acrobat 6.0 or
higher is required for viewing the PDF file on a computer monitor and for
printing the PDF map graphic.

Attention MAC users: If you have problems viewing the pdf files, please download the
pdf file and view it in the lastest verion of Adobe Acrobat.